Don't build option-overloaded packets; they just confuse people (ISC
DHCPD and Windows RIS in particular).
This commit is contained in:
Michael Brown
parent
9125070f51
commit
acd598b4f9
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@ -21,3 +21,11 @@ startrom.com in a hex editor, search for the hex string
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now accept the "F" key instead of "F12".
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DHCP filename
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=============
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Must use Windows backslash separator e.g. 'filename
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"OSChooser\\i386\\startrom.com";', otherwise startrom.com fails to
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correctly identify the path to NTLDR.
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@ -387,12 +387,12 @@ struct dhcphdr {
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*
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* This field may be overridden and contain DHCP options
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*/
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uint8_t sname[64];
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char sname[64];
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/** Boot file name (null terminated)
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*
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* This field may be overridden and contain DHCP options
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*/
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uint8_t file[128];
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char file[128];
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/** DHCP magic cookie
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*
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* Must have the value @c DHCP_MAGIC_COOKIE.
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@ -423,20 +423,6 @@ struct dhcphdr {
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*/
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#define DHCP_MIN_LEN 552
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/** DHCP packet option block fill order
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*
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* This is the order in which option blocks are filled when
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* reassembling a DHCP packet. We fill the smallest field ("sname")
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* first, to maximise the chances of being able to fit large options
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* within fields which are large enough to contain them.
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*/
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enum dhcp_packet_option_block_fill_order {
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OPTS_SNAME = 0,
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OPTS_FILE,
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OPTS_MAIN,
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NUM_OPT_BLOCKS
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};
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/**
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* A DHCP packet
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*
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@ -448,14 +434,8 @@ struct dhcp_packet {
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size_t max_len;
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/** Used length of the DHCP packet buffer */
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size_t len;
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/** DHCP option blocks within a DHCP packet
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*
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* A DHCP packet contains three fields which can be used to
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* contain options: the actual "options" field plus the "file"
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* and "sname" fields (which can be overloaded to contain
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* options).
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*/
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struct dhcp_option_block options[NUM_OPT_BLOCKS];
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/** DHCP options */
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struct dhcp_option_block options;
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};
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/**
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@ -138,7 +138,7 @@ static int set_dhcp_packet_option ( struct dhcp_packet *dhcppkt,
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unsigned int tag, const void *data,
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size_t len ) {
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struct dhcphdr *dhcphdr = dhcppkt->dhcphdr;
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struct dhcp_option_block *options = dhcppkt->options;
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struct dhcp_option_block *options = &dhcppkt->options;
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struct dhcp_option *option = NULL;
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/* Special-case the magic options */
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@ -152,31 +152,23 @@ static int set_dhcp_packet_option ( struct dhcp_packet *dhcppkt,
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case DHCP_EB_SIADDR:
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memcpy ( &dhcphdr->siaddr, data, sizeof ( dhcphdr->siaddr ) );
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return 0;
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case DHCP_MESSAGE_TYPE:
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case DHCP_REQUESTED_ADDRESS:
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case DHCP_PARAMETER_REQUEST_LIST:
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/* These options have to be within the main options
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* block. This doesn't seem to be required by the
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* RFCs, but at least ISC dhcpd refuses to recognise
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* them otherwise.
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*/
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options = &dhcppkt->options[OPTS_MAIN];
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break;
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case DHCP_TFTP_SERVER_NAME:
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strncpy ( dhcphdr->sname, data, sizeof ( dhcphdr->sname ) );
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return 0;
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case DHCP_BOOTFILE_NAME:
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strncpy ( dhcphdr->file, data, sizeof ( dhcphdr->file ) );
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return 0;
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default:
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/* Continue processing as normal */
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break;
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}
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/* Set option in first available options block */
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for ( ; options < &dhcppkt->options[NUM_OPT_BLOCKS] ; options++ ) {
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option = set_dhcp_option ( options, tag, data, len );
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if ( option )
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break;
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}
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/* Set option */
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option = set_dhcp_option ( options, tag, data, len );
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/* Update DHCP packet length */
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dhcppkt->len = ( offsetof ( typeof ( *dhcppkt->dhcphdr ), options )
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+ dhcppkt->options[OPTS_MAIN].len );
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+ dhcppkt->options.len );
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return ( option ? 0 : -ENOSPC );
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}
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@ -296,8 +288,6 @@ int create_dhcp_packet ( struct net_device *netdev, uint8_t msgtype,
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void *data, size_t max_len,
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struct dhcp_packet *dhcppkt ) {
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struct dhcphdr *dhcphdr = data;
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static const uint8_t overloading = ( DHCP_OPTION_OVERLOAD_FILE |
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DHCP_OPTION_OVERLOAD_SNAME );
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int rc;
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/* Sanity check */
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@ -316,20 +306,10 @@ int create_dhcp_packet ( struct net_device *netdev, uint8_t msgtype,
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/* Initialise DHCP packet structure */
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dhcppkt->dhcphdr = dhcphdr;
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dhcppkt->max_len = max_len;
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init_dhcp_options ( &dhcppkt->options[OPTS_MAIN], dhcphdr->options,
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init_dhcp_options ( &dhcppkt->options, dhcphdr->options,
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( max_len -
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offsetof ( typeof ( *dhcphdr ), options ) ) );
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init_dhcp_options ( &dhcppkt->options[OPTS_FILE], dhcphdr->file,
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sizeof ( dhcphdr->file ) );
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init_dhcp_options ( &dhcppkt->options[OPTS_SNAME], dhcphdr->sname,
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sizeof ( dhcphdr->sname ) );
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/* Set DHCP_OPTION_OVERLOAD option within the main options block */
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if ( set_dhcp_option ( &dhcppkt->options[OPTS_MAIN],
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DHCP_OPTION_OVERLOAD, &overloading,
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sizeof ( overloading ) ) == NULL )
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return -ENOSPC;
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/* Set DHCP_MESSAGE_TYPE option */
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if ( ( rc = set_dhcp_packet_option ( dhcppkt, DHCP_MESSAGE_TYPE,
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&msgtype,
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